逛街買衣服的時候，總是會在S和M兩個尺寸之間糾結。每次把自己塞進S號的衣服里，都會頓時很歡喜?？墒牵阌袥]有想過，你穿在身上的S號跟幾年前的S號是一樣大的嗎？

Vanity sizing, also known as size inflation, is used to refer to the phenomenon of ready-to-wear clothing of the same nominal size becoming larger over time.
虛榮尺寸（vanity sizing），也叫做尺寸膨脹，指隨著時代的發展，各類成衣制品在尺寸號碼不變的情況下，實際尺寸增大的現象。

The increasing dimension of garments of the same nominal size has caused some designers to introduce size 0, 00, or subzero sizes. Different manufacturers have modified sizes so that a woman who once wore a size 12 dress can now wear a 10 or an 8.
由于成衣實際尺寸的增大，不少設計師都開始引入“0號”、“00號”，甚至“負0號”尺寸。不同的成衣生產廠家也調整了各自的尺寸號碼規則，原來穿12號衣服的女性現在能穿10號或者8號的衣服。

Many commentators have suggested that "vanity" sizing, as its name suggests, is designed to satisfy buyers' wishes to appear thin and feel better about themselves. While some others also suggests that vanity sizing allows clothing companies to cater their sizing to their demographic, since women of different sizes may be attracted to different brands. Finally, it has been suggested that vanity sizing merely reflects the increasing prevalence of obesity.
很多評論人士都表示，“虛榮尺寸”就是為了滿足消費者想要看上去瘦一點兒的虛榮心理。不過，也有人表示，“虛榮尺寸”讓成衣公司能夠根據目標消費人群的特征來調整產品的尺寸，因為不同身材的女性可能鐘情的品牌也不盡相同。總的來說，“虛榮尺寸”的出現說明肥胖人士增多了。

（中國日報網英語點津 Helen）